The Delta switches offer three levels of surge protection! In the common position the common is disconnected from all antennas and all antennas are connected to ground. These switches feature a built-in surge protector. A replaceable D-4 Arc-Plug cartridge will divert harmful surges to ground. (Note: The Delta switches reduce the hazard of lightning induced surges. They will not prevent fire or damage caused by a direct strike). Made in the U.S.A.

The Delta 2B and Delta 4B switches feature SO-239 fittings (for PL-259s).
The Delta-2B/N and Delta-4B/N switches are the same except with 'N' jacks instead of SO-239s.

These new "B" models are the same as the original version, but with these enhancements:
New precision machined shaft, higher strength, lower resistance silver bearing solder and new brass ARC-Plug housing.